This fine structure was founded in 1361 by the Conventual Franciscans and is the oldest church in San Marino. Built by the Comacine Masters, still holds symbols and inscriptions on the stone of the western wall, as well as a commemorative plaque in local stone over the door of the Church. It was frescoed by Antonio Alberti da Ferrara in the early decades of the fifteenth century, while the wooden crucifix inside dates from the fourteenth century. The interior was radically restructured in the late eighteenth century. Since 1966, the former Franciscan convent has housed a museum, which consists of two sections: sacred art and art gallery. You can enjoy the works of the artistic heritage of the monastery and of other Franciscan churches, paintings on wood and canvas, a precious fresco and vestments from the 14th to the 18th century. In the gallery there are works by the artist Emilio Ambron, consisting of paintings and sculptures from the first half of the twentieth century donated by the author himself.